A viewing angle range (viewing angle for short) is an important performance index of a liquid crystal display panel. It is necessary for a liquid crystal display panel to vary a polarization state of light transmitted therethrough via adjusting orientation of liquid crystal molecules, so as to achieve a display function. Due to influences of optical anisotropy of liquid crystal molecules, a liquid crystal display device has a smaller viewing angle than a cathode-ray tube display device. In order to increase the viewing angle of the liquid crystal display device, the techniques of vertical alignment (VA) mode, pattern vertical alignment (PVA) mode, multi-domain vertical alignment (MVA) mode, in-plane switching (IPS) mode, fringe field switching (FFS) mode are successively proposed as technologies constantly develop, thereby achieving wide viewing angle display of the liquid crystal display device.
Although liquid crystal display panels tend to have wider viewing angles now, under certain conditions, a switching function between a wide viewing angle and a narrow viewing angle is still necessary for a liquid crystal display panel. This is especially true for a portable electronic apparatus, e.g., a mobile phone, a pocket computer, or a notebook computer, which uses a liquid crystal display device. For instance, a user may, sometimes need to share images stored in the portable electronic apparatus with other persons, while at other times, expect to protect the images stored in the portable electronic apparatus from other persons as privacy. Therefore, it is necessary to provide a liquid crystal display panel with a switchable viewing angle.
In the prior art, researchers have put forward the following solutions to switching between a wide viewing angle and a narrow viewing angle.
To start with, a shutter shielding film can be used. When a user expects the liquid crystal display to display pictures at a narrow viewing angle, a shutter shielding film can be coated on a screen of the liquid crystal display panel. Such a procedure is inconvenient to operate. Besides, the user has to take the shutter shielding film along with him/her.
Moreover, a double backlight system can be used. According to the double backlight system, an ordinary backlight system can be used to achieve wide viewing angle display, and a collimating backlight system can be further used to achieve narrow viewing angle display. This system will undoubtedly increase manufacturing costs, thickness, and energy consumption of the liquid crystal display panel.
In addition, a double-layer liquid crystal display panel can be used. That is, a main liquid crystal display panel can be used to display images normally, and an additional liquid crystal display panel can be employed to control viewing angles for display. This double-layer liquid crystal display panel will also increase manufacturing costs, thickness, and energy consumption of the liquid crystal display panel.
Obviously, none of the above liquid crystal display panels can satisfy the requirements of a portable electronic apparatus for size or energy consumption.
Therefore, the inventor of the present disclosure, based on practical experience in designing and manufacturing liquid crystal display panels, and relevant professional knowledge thereof, has proposed a liquid crystal display panel with a switchable viewing angle, which has a simpler structure and is more convenient to operate, thereby satisfying high requirements of portable electronic apparatuses, such as mobile phones, for stable circuits, weight, and energy consumption.